Synesthesia is believed to occur due to cross-wiring in the brain; synesthetes have more synaptic connections than 'normal' people and some are interconnected in ways others are not, including across brain regions. Since the brain regions responsible for the processing of each type of sensory stimuli are intensely interconnected, synesthetes see or taste a sound, feel a taste, or associate people with a particular color.
A new paper in Consciousness and Cognition is the first time that a scientific explanation is attempted for this esoteric aura, a supposed energy field of luminous radiation surrounding a person as a halo, which is imperceptible to most human beings but healers claim they can detect. University of Granada Department of Experimental Psychology researchers Óscar Iborra, Luis Pastor and Emilio Gómez Milán state, "Not all healers are synesthetes, but there is a higher prevalence of this phenomenon among them. The same occurs among painters and artists, for example".
For the paper, the researchers interviewed synesthetes like "Esteban Sánchez Casas", known as "El Santón de Baza", who claim to be able to see and heal the auras of people.
Some people attribute 'paranormal powers to El Santón, such as his ability to see the aura of people "but, in fact, it is a clear case of synesthesia", the researchers explain. El Santón presents schizotypy (certain personality traits in healthy people involving slight paranoia and delusions), face-color synesthesia (the brain region responsible for face recognition is associated with the color-processing region); touch-mirror synesthesia (when the synesthete observes a person who is being touched or is experiencing pain, s/he experiences the same) and high empathy (the ability to feel what other person is feeling). "These capacities make synesthetes have the ability to make people feel understood, and provide them with special emotion and pain reading skills", the researchers explain.
In the light of the results obtained, the researchers remark the significant "placebo effect" that healers have on people, "though some healers really have the ability to see people's auras and feel the pain in others due to synesthesia". Some healers "have abilities and attitudes that make them believe in their ability to heal other people, but it is actually a case of self-deception, as synesthesia is not an extrasensory power, but a subjective and 'adorned' perception of reality", the researchers state.
E.G. Milána, O. Iborraa, M. Hochela, M.A. Rodríguez Artachoa, L.C. Delgado-Pastora, E. Salazara, A. González-Hernández, 'Auras in mysticism and synaesthesia: a comparison', Consciousness and cognition, 2012, 21(1), 258-268 http://dx.doi.org/10.1016/j.concog.2011.11.010